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A cephalopod / ˈ s ɛ f ə l ə p ɒ d / is ... for instance, radulae have only been found in nine of the 43 ammonite genera, [106] and they are rarer still in non ...
Prehistoric cephalopod genera (2 C, 73 P) T. Todarodes (6 P) U. Uroteuthis (10 P) Pages in category "Cephalopod genera"
The cephalopods have a long geological history, with the first nautiloids found in late Cambrian strata. [1]The class developed during the middle Cambrian, and underwent pulses of diversification during the Ordovician period [2] to become diverse and dominant in the Paleozoic and Mesozoic seas.
Pages in category "Prehistoric cephalopod genera" The following 73 pages are in this category, out of 73 total. This list may not reflect recent changes. A.
These genera were once considered ancestral cephalopods, [1] but are more broadly assigned to the helcionellids (or putatively the tergomyans); i.e. "Cambrian monoplacophora". [ 2 ] References
Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as well as ancestral forms from the Upper Permian, the exception being the phylloceratids which gave rise to the great diversity of post-Triassic ammonites.
The taxonomic placement of Trachyteuthis is uncertain. Though often assigned to the order Vampyromorphida, the discovery of fossilised Trachyteuthis beaks in the Upper Jurassic limestone of Germany suggests a close phylogenetic relation to the Octopoda.
Gymnitidae is a family of Lower to Middle Triassic ammonite cephalopods with evolute, discoidal shells.. Hyatt and Smith (1905, p. 114-115) included the Gymnitidae in the suborder Ceratitoidea, which later became the superfamily Ceratitaceae and included in it genera more primitive than Gymnites as well as the more advanced Gymnites.